Coumarin anticoagulants e.g. warfarin, heparin and thrombolytic agents; NSAIDs; methotrexate; antidiabetic agents; probenecid, sulfinpyrazone, phenylbutazone; antacids. Drugs metabolized by CYP450 e.g. phenytoin, tamoxifen, tolbutamide, torsemide, fluvastatin.